OBJECTIVES: (1) To gather, in a prospective fashion, sera from patients with sarcoma, their immediate and distant family members and suitable age and sex-matched controls. (2) To use such sera, particularly those from immediate family members, to search for new sarcoma-related antigens that may only be expressed in persons who have successfully mounted an immune response against the etiologic agent of sarcomas. (3) To survey the sera gathered to determine the presence of antibody to S1, S2, S3 and any newly identified sarcoma-related antigens. Such determinations will be serial for each individual followed in order to observe the frequency of seroconversion. By comparing antibody prevalence and the ratio of seroconversion to sarcoma antigens in immediate and distant family members it is intended to learn whether any of the sarcoma antigens are likely to be associated with a transmissible agent.